Add some great knowledge to your brain today!
You will need to put your thinking cap on for this "Post of the Day". There is no visual feast here but more of economic and political concepts that come into play in the oil industry.
Don't click away thinking this is boring. The post by Robert Rapier of the Oil Drum provides an easy to understand explanation why the summer blend switchover causes oil prices to rise in spring time! It also explains how the environment benefits from this practice.